The present invention relates to an apparatus and a method for folding and tucking disposable diapers in crotch regions inwardly of the diaper as the diaper is fed in a machine direction.
Various processes for making pull-on diapers are well known, (for example, from Japanese Laid-Open Patent Application Publications Nos. 1993-31135A, 1993-31136A and 1993-42180A). A typical example of the well-known processes will be described below.
The process comprises the steps of forming a contiguous laminated structure by interposing liquid-absorbent cores at regular intervals between a liquid-pervious continuous first web and a liquid-impervious continuous second web both running in a machine direction so that each of the liquid-absorbent cores may be arranged in a cross direction orthogonal to the machine direction, folding back the contiguous laminated structure along a center line extending in the machine direction with the second web inside, joining these webs along a heat-sealing line extending in the cross direction between each pair of the liquid-absorbent cores adjacent to each other, cutting out portions of the contiguous laminated structure along first cutting lines each being convex in the cross direction symmetrically about the center line to form leg-holes and finally cutting the contiguous diaper structure along second cutting lines each extending in the cross direction between each pair of the heat-sealing lines to obtain a plurality of individual pull-on diapers. The pull-on diaper made by such conventional process is composed of a front waist region, a rear waist region and a crotch region so as to define a waist-hole and a pair of leg-holes.
In the case of the diaper made by the process as has exemplarily been described above, the leg-holes open laterally with respect to the waist-hole which opens in a vertical direction as viewed from above with the waist-hole broadened with the hands. In other words, the waist-hole is out of linear alignment with the leg-holes and the crotch region lies right against the waist-hole. With such diaper, the wearer's toes or heels are prone to get stuck on transversely opposite side edges of the crotch region as the wearer's legs are let through the waist-hole and the leg-holes when the diaper is put on the wearer's body. In consequence, a much time may be taken to put the diaper on the wearer's body.
From the other viewpoint also, such diaper is inconvenient due to the minimum width of the crotch region usually being larger than that of the wearer's crotch region. Specifically, the crotch region of the diaper is too bulky to be properly received by the wearer's crotch region and causes the wearer to feel an incompatibility. Furthermore, the crotch region may be irregular folded and/or formed with a plurality of irregular creases as the crotch region of the diaper is squeezed between the wearer's thighs. As a result, a body discharge absorbing function expected to the diaper in the crotch region is apt to be deteriorated and body discharges may leak beyond the crotch region of the diaper.
None of the processes disclosed in the above-cited Publications includes means for folding the diaper in the crotch region and therefore the diapers made by these processes are still accompanied with the problems as have been described above.